astro3 Flashcards
what are the seasonal patterns in uranus
42 yrs of continuous
daylight followed by 42 yrs of darkness at poles
what causes the extreme seasonal patterns in uranus
Probably caused by a major collision when/right
after it formed
what drives a swirl of storms in uranus
The huge difference in temperature between the long illuminated &
dark sides
how many rings of uranus are known
It has 13 known rings.
describe the rings uranus
Narrow (a few km) and made of very dark particles, which vary in size from
μm to a fraction of a metre.
what are the 5 main moons of uranus
Miranda, Ariel, Umbriel,
Titania, and Oberon.
what is the thing that happens when aarav calls neel for 2 min (Mom And Uncle Talk Only)
Miranda, Ariel, Umbriel,
Titania, and Oberon. 5 main moons of uranus
when were the moons of uranus discovered
Discovered only in 18th century by Herschel
which planet is very similar to uranus in size and composition
neptune
describe neptune in comparison to uranus
More massive due to larger density
More intense blue color (not known why, CH4 may
have only a minor contribution)
wind speeds in neptune
Its winds are the fastest in the Solar system,
reaching up to ~2,500 km/h!
what is the interior of neptune made of
ices and rock
what causes the wind speeds in neptune
must be due
to an internal energy (heat?) source
describe neptune in comparison to uranus in terms of radiation lol
Unlike Uranus which only radiates 1.1 × as much energy as it receives from the Sun, Neptune radiates ~2.6…2.7× as much energy as it receives from the Sun
when was neptune discovered
Discovered in 19th century after theoretical
calculations
describe neptune’s distance from the sun in comparison to pluto
Although Pluto’s mean distance from the Sun is
greater, its orbit is so eccentric that for about 20
years of each revolution Pluto is actually nearer the
Sun than is Neptune!
describe the ring system of neptune
faint and fragmented
ring system discovered in 1984. May consist of ice particles coated
with other materials, which
probably gives them a reddish hue
when was pluto discovered
1930, and From its surface Sun is just a slightly brighter star
describe the orbit of pluto
Eccentric orbit, also inclined to the ecliptic plane.
The ecliptic plane is defined as
the imaginary plane containing the Earth’s orbit around the sun
zenith
the point in the sky or celestial sphere directly above an observer.
meridian
is the half of an imaginary polar great circle or great ellipse on the Earth’s surface, a coordinate line terminated by the North Pole and the South Pole.
tell me again what’s the meridian
A meridian is the locus connecting points of equal longitude
tell me about the rotation of pluto
it rotates on its “side” in its orbital plane
what is pluto made of
ice and rock
how many moons does pluto have
Has 5 moons
what is pluto’s surface made of
Its surface has plains mostly composed of nitrogen ice, also mountains
of water ice.
what’s under pluto’s thick ice crust
It may harbor a liquid H2O ocean under a thick ice crust
what is the atmosphere of pluto like
Has a tenuous, thin, yet hazy atmosphere made of N2, CH4 & CO
what happened to the vast majority of hydrogen & helium gas never became part of any planet
They were cleared away by radiation & solar wind from the young Sun. Solar wind = stream of charged particles continually emitted from the Sun
was the solar wind was much stronger when the Sun was young
yes because the young Sun spun very fast (conserve angular momentum!) much stronger magnetic field than today
what did clearing of the gas in the nebula do in the nebular theory
sealed the compositional fate of the planets
describe the formation of the jovian planets
began as large icy planetesimals, which
captured H, He & other gases from the Solar nebula.
Their gravity grew stronger as they accumulated matter, allowing
them to capture even more matter (positive feedback)
Each Jovian planet became surrounded by its own
(micro)accretion disk of gas, spinning in the same
direction as the planet’s rotation.
describe the formation of the moons of the jovian planets
accreted from icy planetesimals within these disk ended up
with nearly circular orbits in the same direction as the planet’s
rotation and lying in (or close to) the planet’s equatorial plane
what happened as the jovians planets formed
they quickly cleared away their orbital
path inside the Solar nebula
Formation of terrestrial planets
“Solid seeds of metal
& rock in the inner Solar nebula grew through the
accretion process.
Microscopic particles stick together through electrostatic forces
As they
grow larger, their surface area ↑ ↑
easier to make contact with others!
Particles grew in mass until they became planetesimals, where
gravity dominated in the accretion process
For larger planetismals, collisions were increasingly destructive
These planetesimals eventually assembled into terrestrial planets,
which are relatively small in size because rock & metal made up only a
small amount of the materials in the Solar nebula”
Origin of asteroids & comets
"Asteroids = rocky leftover planetesimals of the inner Solar system Comets = icy leftover planetesimals of the outer Solar system The solar wind cleared the leftover gas, but not the leftover planetesimals! Leftover icy planetesimals between Jovian planets either collided with the Jovian planets or were gravitationally flung into the Oort cloud (hence their random orbits). Those beyond Neptune’s orbit remained in the Kuiper belt. The nebular theory predicted the Kuiper belt & Oort cloud 40 years before their actual observation. "
Origin of asteroids & comets (cont’d)
“ Asteroids & comets today represent a small fraction of the leftover
planetesimals. Most were flung out by gravitational encounters but
many collided with planets
→ The huge majority of these collisions
occurred in the first few hundreds of
m of years of our Solar
system’s history
= the Heavy Bombardment
Brought essential materials from other regions of solar system, e.g. water &
air on Earth
Impact craters left behind on solid worlds
Provided a few captured moons
Most asteroids ended up in the asteroid belt.
Jupiter’s gravity prevented a planet (Phaeton) from forming there.”
the most likely
explanations for most of the exceptions to our general planetary
rules
Random giant impacts
